From: Tomohiro Kusumi Date: Tue, 27 Jun 2017 10:21:03 +0000 (+0300) Subject: HOWTO: add offset unit info for offset= option X-Git-Tag: fio-2.99~23 X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=82dbb8cbf00b0e70d8ca55d484fedf588c1bcb33 HOWTO: add offset unit info for offset= option Add "in bytes" and "A percentage can be specified by ...", based on an email post titled "in what units is offset option?". -- example of offset in percentage # ./fio --debug=parse --name=xxxxx --ioengine=sync --rw=rw --size=1m --unlink=1 --offset=-51 | grep "SET start_offset_percent" parse 12859 SET start_offset_percent 50 Signed-off-by: Tomohiro Kusumi Signed-off-by: Jens Axboe --- diff --git a/HOWTO b/HOWTO index 012bca84..37caa3c0 100644 --- a/HOWTO +++ b/HOWTO @@ -1090,11 +1090,13 @@ I/O type .. option:: offset=int - Start I/O at the provided offset in the file, given as either a fixed size or - a percentage. If a percentage is given, the next ``blockalign``-ed offset - will be used. Data before the given offset will not be touched. This + Start I/O at the provided offset in the file, given as either a fixed size in + bytes or a percentage. If a percentage is given, the next ``blockalign``-ed + offset will be used. Data before the given offset will not be touched. This effectively caps the file size at `real_size - offset`. Can be combined with :option:`size` to constrain the start and end range of the I/O workload. + A percentage can be specified by the percentage number plus 1 with preceding '-'. + For example, -1 is parsed as 0%, -10 is parsed as 9%, -101 is parsed as 100%. .. option:: offset_increment=int